Conventionally, a card reader has been known which is attached and used in a host device such as an ATM (Automated Teller Machine) (see, for example, Patent Literature 1). In the card reader described in Patent Literature 1, an attaching recessed part is formed on a back face of a main body frame of a card processing part where reproduction of information recorded in a card and recording of information to the card are performed. A bottom face of the attaching recessed part is an attaching reference face for attaching the card reader to the host device. Further, a detection mechanism for detecting that the card reader has been detached from the host device is disposed in the attaching recessed part. The detection mechanism includes a sheet switch.
In a case that the card reader described in Patent Literature 1 has been attached to the host device, the sheet switch is pushed by a tip end face of an abutting protruded part formed in the host device and the sheet switch is set in an “ON” state. On the other hand, when the card reader is detached from the host device, the sheet switch is separated from the tip end face of the abutting protruded part and thus the sheet switch is turned to an “OFF” state. Therefore, in the card reader described in Patent Literature 1, the sheet switch is switched from an “ON” state to an “OFF” state and thereby it is detected that the card reader has been detached from the host device.